Calcite & Coconut Shell GAC Filter Cartridge

Water that tastes flat or faintly metallic. Blue-green stains under the faucet. A test report that reads acidic or very soft. Low-pH, low-mineral water is aggressive: it pulls metal from the plumbing it travels through and can taste lifeless in the glass.

This Calcite & Coconut Shell GAC Filter Cartridge answers both problems in one stage. Natural calcite, a calcium carbonate mineral, dissolves slowly into soft or acidic water to raise its pH and add calcium back, and coconut shell granular activated carbon polishes taste and odor before the water leaves the cartridge. Four sizes fit standard 2.5 x 10, 2.5 x 20, 5 x 10 and 5 x 20 inch housings, including Crystal Quest countertop, under-sink and whole house systems, with published capacities from 3,000 to 18,000 gallons.

At a glance

• Raises low pH naturally: calcite neutralizes acidity by dissolving into the water, with no chemical feed
• Self-limiting: calcite corrects toward a neutral, non-corrosive balance and does not overshoot under normal conditions
• Carbon polish built in: coconut shell GAC improves taste and odor in the same cartridge
• Published capacity per size: 3,000 to 18,000 gallons at under 100 ppm hardness
• Four sizes, 0.5 to 6 GPM, with a typical life of 12 to 24 months

What you are looking at

The cartridge is a polypropylene casing with polypropylene end caps, filled with a mixed bed of white calcite granules and black coconut shell carbon. A polypropylene expansion pad keeps the bed packed, a spun polypropylene post-filter sits at the outlet, and a Buna-N gasket on top seals against the housing cap. Each end cap has 1-micron pads behind its openings.

How a calcite filter works

Neutralizing acidity with calcium carbonate

Acidic water is hungry for minerals. When it flows through calcite, it dissolves a small amount of the calcium carbonate, and that reaction consumes the acidity and raises the pH. The more acidic the water, the more calcite it dissolves; as the water approaches a neutral balance the reaction slows on its own. That self-limiting behavior is why calcite is the classic, forgiving choice for correcting low pH.

Remineralization

The calcium that dissolves stays in the water. That is the point for very soft or low-mineral water: it gains back some of the mineral content that gives water body and helps it sit in balance with your pipes. It also means calcite adds a little hardness, which is normal and expected.

Coconut shell GAC as the polishing stage

Activated carbon is honeycombed with microscopic pores that hold on to the organic compounds behind off tastes and odors. Here the coconut shell GAC acts as a post-polisher inside the cartridge, so the water that comes out tastes clean as well as balanced.

Why calcite gets used up

Calcite works by dissolving, so the bed slowly shrinks as it treats water. More acidic water and higher use consume it faster. That is why each size carries a gallon estimate and why replacement on schedule matters more here than with a purely mechanical filter.

What it treats

Primary jobs:

• Low pH and acidity: raises pH toward neutral
• Low-mineral, very soft water: adds calcium back
• Taste and odor: coconut shell GAC polishing, including chlorine taste

Where it helps your plumbing: in a whole house housing, water that has been brought toward neutral before it reaches your pipes is less corrosive to copper and brass. In a countertop or under-sink system, it balances the water you drink and cook with at that tap.

Not designed to treat: bacteria and viruses, fluoride, nitrate, lead and other heavy metals, iron, or high VOC and chloramine loads (the carbon here is a polishing stage, not a full carbon stage). It is not for water that is already neutral or alkaline. For those jobs, see the GAC Filter Cartridge, the Lead Filter Cartridge and Crystal Quest's fluoride and reverse osmosis options.

Why Crystal Quest

• Two treatments, one housing. pH correction and carbon polishing in a single cartridge saves a stage and a housing.
• Capacity you can plan around. Every size publishes a gallon estimate and its test condition, so you can match the cartridge to your daily use.
• Over 1,000,000 people served since 1994. Crystal Quest builds under ISO 9001 quality management and has made water filtration in the USA for over 30 years.
• Lifetime support. Send us your water test and our team will tell you whether calcite is the right correction for it.

Where it fits

• Systems that specify calcite and coconut shell GAC: Crystal Quest countertop, under-sink and whole house cartridge housings
• Acidic well water or very soft water where a test shows low pH
• Not the alkaline mineralizer: this cartridge is calcite plus coconut GAC; the separate alkaline mineralizer uses a calcium and magnesium blend, and the phosphate and GAC cartridge is a different treatment again

Pick the size printed on your current cartridge or in your order history: 2-7/8" x 9-3/4" (CQE-RC-04012), 2-7/8" x 20" (CQE-RC-04024), 4-5/8" x 9-3/4" (CQE-RC-04075) or 4-5/8" x 20" (CQE-RC-04080).

Common questions